Amblyopia is characterized by poor or indistinct vision in an eye. It is one of the most common children ophthalmic disorders; it affects 1-5% of the population, and is generally associated with a history of strabismus, anisometropia, or deprivation of vision early in life by vision-obstructing disorders such as congenital cataract. Amblyopia is a developmental problem in the brain, not an organic problem in the eye. The part of the brain receiving the visual information from the affected eye is not stimulated properly, and develops abnormally. Blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging (fMRI) is a widely used brain mapping technique, which can be used to evaluate the neural activity in the brain by measuring the blood flow to the local vasculature. More recently, fMRI has enabled the noninvasive investigation of brain cortical function in human amblyopia. It has been found that amblyopia is associated with lesions in the striate cortex (Brodmann area 17) and lateral geniculate nucleus (LGN) (Int J Med Sci 2012, 9 (1), 115-120).
An adult brain also poses some plasticity; however, it is much more limited than in an infant brain. However, there are certain conditions which can facilitate a circuit rewiring in a mature brain. At a cellular and molecular level, the adult plasticity is dynamically limited. Some of these “brakes” are structural, such as perineuronal nets or myelin, which inhibit neurite outgrowth. Others are functional, acting directly upon excitatory-inhibitory balance within local circuits (J. of Neuroscience, 2010, 30 (45), 14964-14971). It is contemplated that the plasticity in the childhood and adulthood may be induced by lifting these brakes through the exposure to a customized video content.
The conventional treatment of amblyopia involves full or part-time patching of the strong eye in order to force the use of the deficient eye. Owing to the risk to the strong eye, full-time patching is rarely employed nowadays. Since the critical period in humans is generally thought to end at 7-8 years of age, it is not surprising that the outcome of occlusion treatment is better in younger children than in those older than 6 years (Invest Ophthalmol Vis Sci. 2004, 45 (9), 3048-54). However, the full-time occlusion has been reported to be successful in children aged 9-14 years (Eye (Lond). 2004, 18 (6), 571-4), and the part-time occlusion (with patching of 2-6 hours per day) in children aged 7-17 years (Arch Ophthalmol. 2005, 123 (4), 437-47); in most children aged 7-12 years, the improvement in acuity persists for at least a year after termination of patching (Arch Ophthalmol. 2007, 125 (5), 655-9). Even patients aged 13-17 years may still respond positively to the part-time patching if they have not been treated previously, although it is not yet known whether their visual acuity improvement is permanent (Arch Ophthalmol. 2005, 123 (4), 437-47). However, the greatest threat to a successful patching treatment of amblyopia in little children is a lack of compliance.
Thus it is strong felt and unmet need to provide an amblyopia treatment through a visual stimulation system and method.